10 Seconds Flat Foot Sport Insoles use a Poron Cellular Urethane layer for athletic cushioning. Poron is light weight & durable, it does not harden like PVC foam, does not breakdown like Latex foam or take a compression set like EVA foam. The problems associated with over-pronation are prevented by the Flat Foot Insole. The patented design aligns the ankle and supports the foot from Mid-Stance to Toe-off. People with low arches can find pain relief by using this product.